Natural selection, adaptations, genetic variation, and population evolution are all related in terms of changes in phenotypes over time. Evaluate which statement appropriately describes the relationship between the concepts of natural selection, adaptations, genetic variation, and population evolution and select the best choice. A) Genetic variation exists in a population. Some of the genetic variation results in different phenotypes. The phenotypes that enhance survival are called adaptations. Individuals with well-adapted phenotypes are more likely to survive and reproduce, leading to population evolution over generations.
B) Adaptations exist in certain individuals in a population. The increase in adaptations causes an increase in genetic variation. The adaptations that enhance survival lead to larger populations, which further increases genetic variation. Individuals with well-adapted phenotypes are more likely to survive and reproduce, leading to population evolution over generations.
C) Genetic variation is high in a population, but random events cause it to decrease. Populations with fewer individuals and lower genetic diversity are able to undergo natural selection when selective pressures are high. The increase in selective pressure causes an increase in adaptations that are better suited for survival. This results in an evolutionary change of a population.
D) Selective pressures exist in nature and cause changes in a population. Populations with high selective pressures have higher rates of genetic change, leading to an increase in genetic variation. Increased genetic variation leads to some individuals having well-suited adaptations. The presence of these new adaptations is evidence that the population has changed, or undergone evolution.